Common knowledge dictates that girls dig guys with muscles. However, new research suggests that women gave up on bulging biceps and strong jawlines long ago, in favor of qualities like loyalty and generosity. In other words, the scrawny geek gets the gal.

The research, which was conducted at the University of Tennessee-Knoxville and is published in PNAS, used mathematical models to get to the bottom of when humans first started living in monogamous relationships. The study suggests that the rise of weaker males—or Beta males, if you prefer—began far earlier than suspected. In fact, Beta males started to become a hit with the ladies not long after humans started living in large social groups.

When humans began living in such groups, Alpha males were clearly dominant. But over time, Beta males realised that they had to develop strategies in order to secure a relationship. Their solution was to devote themselves to single woman—unlike Alpha males who played, and continue to play, the field—offering her all the food and protection she needed. On balance, the research suggests, women quickly became more convinced by the notion of a committed and generous partner over that of a stronger, but promiscuous, man.

So, while women may find men with muscle attractive, in the long term its the weakling that wins out. [PNAS via The Telegraph]